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Hello All! I wonder if someone here has the knowledge to solve a very annoying problem I have been facing lately: I create Porcelain plates, about 9" in diameter. The wight of each plate after glaze firing is about 200 to 250 grams which makes them pretty thin. When bisque firing them, all is well - Always. When glaze firing them (1230 C) , many many of the plates are broken WHEN TOUCHED, that means that when I open the kiln, they all look fine but when I come to pick them up, they break up in my hands. Those that do make it in one piece, have a hollow sound when knocked and break soon after. A few facts to add to the mystery: 1. I do not use a slab roller. 2. Other plates that have a wavy edge style also made from the same Porcelain and with the same method do not break at all IN THE SAME FIRING, 3. Some plates do come out OK. 4. Am using an electric Kiln. 5. The plates are only glazed on their top side. 6. Some plates have a supporting ring element (made also from Porcelain) underneath their circumference to keep their shape (raised edges) and some don't. They all break. 7. The plates are bone dry when entering the glaze firing - the glaze is air dried for a few hours before I fire up the kiln. Any help on this issue will be greatly appreciated! Thank you, Diana.